用括号内所给词的适当形式填空。
1. There are (nineteen) floors in the building, and I live on the (twelve) floor.
2. Do you know how (ask) for information politely?
3. Would you please (lend) me some (write) paper?
4. We need (speak) more English every day to improve our (speak) English.
5. We should be careful when (cross) the street.
6. The old should be spoken to (polite). We must be (polite) to the old.
7. Have you made a (decide) to help your friend?
8. My parents have decided (take) a vacation with me in Hainan Island this summer.
Why not (join) us?
9. On weekdays the mall is (crowd) but on weekends it's (crowd), so I often
go to the mall on weekdays.
10. I've (forget) to tell you I went to (Uncle Bob) yesterday morning.